My WB Caprice has been very reliable considering its age and mileage. The engine still runs very smoothly and does not burn oil. Most of the work I have had done on it has been preventive maintenance, rather than an absolutely necessary repair.
There is some rear seal wear and a crack in the sump gasket so there is a minor seepage of oil if it isn't run regularly.
In 2000 I had the transmission and power steering box rebuilt due to slight fluid leakage.
In 2001 I replaced the upper engine gaskets and had the LSD diff beefed up a bit and now runs 3.08 gearing.
In 2002 I had to replace the idler arm, have the power steering box rebuilt (again) and the lower control arm bushes in the suspension replaced.
In 2003 I have made a minor radiator repair and some minor rust correction and repainting will be undertaken later on, and possibly some further suspension work. Hopefully I will be able to get the air conditioning working again soon too (it wasn't functional when I bought the car).
The Statesman's are great cruisers that have distinctive (almost) American styling and a comfort level that is unmatched in any other Australian car, and even over 20 years on still boasts a range of standard options that are up with the best of modern vehicles.
The key to their reliability is the inherent simplicity and ruggedness of the engine/drive-train and electrical systems, which typically use heavy-duty components and loadings somewhat less than they are capable of withstanding.
My only reservation with the standard setup of the Statesman's is that they have only a 5 litre motor and a 3-speed auto, which usually means the engine is running between 2200-2500RPM at highway speeds, which is not particularly efficient in a V8. If it had a 5.7 or 6.0 litre motor with a bit more horsepower and a lock-up torque converter, it'd have a bit more 'pep' up hills and be more economical. The good news is you can do that sort of work with aftermarket parts for surprisingly little cost.
The handling in my car is a bit iffy due to a previous owner putting in chopped springs to lower it, so it looks fantastic, but is a bit disconcerting on a rainy day on winding roads in hilly country. Pedders and other companies such as Tubular Suspension Systems offer aftermarket upgrades that vastly improve the ride, safety and handling of a lowered WB whilst still being legal, and that is one of my next missions with it.
Given the sheer mass of the statesman, you are probably never going to win any prizes in a drag race no matter how much horsepower it can pump out, but even in standard form it performs credibly. Even small upgrades to the engine, whether by increasing the cubes or putting in a decent camshaft will make a big difference to the performance. I'm convinced it was produced to be a towing engine, and it is fantastic for doing that, but really needs more horsepower to make it accelerate like you'd expect a V8 to.